18.3: Applications of Raman Spectroscopy

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    From LibreTexts, under CC BY-NC-SA 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Raman spectroscopy is useful for both qualitative and quantitative analyses, examples of which are provided in this section.

    Qualitative Applications

    There are numerous databases that provide reference spectra for inorganic compounds, for minerals, for synthetic organic pigments, for natural and synthetic inorganic and organic pigments, and for carbohydrates. Such data bases are often searchable by not only name and formula, but by the prominent Raman scattering lines. Examples of spectra are included here using data from the databases linked to above.

    Examples of Raman spectra for the mineral calcite.
    Examples of Raman spectra for the organic pigment alizarine red.
    Examples of Raman spectra for the inorganic pigment azurite.
    Examples of Raman spectra for the carbohydrate fructose.
    Figure \(\PageIndex{1}\): Examples of Raman spectra for the mineral calcite (CaCO3), the organic pigment alizarine red (C14H7NaO7S), the inorganic pigment azurite (Cu3(CO3)2(OH)2), and the carbohydrate fructose (C6H12O6). The data for these spectra were obtained from the databases linked to at the beginning of this section.

    Quantitative Applications

    The intensity of Raman scattering, \(I(\nu)_R\), is directly proportional to the intensity of the source radiation, \(I_l\), and the concentration of the scattering species, \(C\). The direct proportionality between \(I(\nu)_R\) and \(I_l\) is important given that each photon experiencing Raman scattering requires approximately \(10^8\) excitation photons. Using a laser as a source of radiation and increasing its power leads to an improvement in sensitivity. The direct proportionality between \(I(\nu)_R\) and the concentration of the scattering species means that a calibration curve of band intensity (or band area) is a linear function of concentration, allowing for a quantitative analysis.

    This page titled 18.3: Applications of Raman Spectroscopy was last modified on Mon, 24 Oct 2022 14:54:58 GMT and is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by David Harvey.